Process for preparing lactones

ABSTRACT

New methods for the preparation of lactones possessing odoriferous properties and containing 14 to 17 ring carbon atoms in their molecule.

United States Patent [191 Becker PROCESS FOR PREPARING LACTONES [75] Inventor: Joseph J. Becker, Geneva,

Switzerland [73] Assignee: Firmenich S.A., Geneva,

Switzerland [22] Filed: July 9, 1973 [21] App]. No.: 377,564

Related 0.8. Application Data [62] Division of Ser. No. 41,595, May 28, 1970,

abandoned.

[30] Foreign Application Priority Data May 29, 1969 Switzerland 8192/69 May 27, 1970 Switzerland 7865/70 [52] US. Cl. 260/343; 252/522; 260/345.2;

[451 June 17, 1975 204/158 R [51] Int. Cl; C07d 9/00 [58] Field of Search 260/343 [56] References Cited UNITED STATES PATENTS 3,528,898 9/1970 Story 260/343 3,546,251 12/1970 Matsumoto 260/343 Primary Examiner lohn M. Ford Attorney, Agent, or Firm-Pennie & Edmonds [5 7 ABSTRACT New methods for the preparation of lactones possessing odoriferous properties and containing 14 to 17 ring carbon atoms in their molecule.

13 Claims, No Drawings PROCESS FOR PREPARING LACTONES This is a division of application Serial No. 41,595 filed May 28, 1970 now abandoned.

SUMMARY OF THE INVENTION The invention relates to a new method for the preparation of lactones having the formula i-o cn-R (CH CH-R III ll (en c 0 ca a containing one double bond in one of the positions indicated by the dotted lines, and wherein r is Zero or 1, m is l or 2 and p is an integer from Zero to 2, and R and R have the same' meaning as indicated above. Said lactones, some of which are new compounds, possess interesting odoriferous properties and, consequently, are, useful in the perfume industry as performing and fragrance modifying agents for the manufacture of perfumes and perfumed products.

DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the invention the method for preparing lactones Ill comprises cleaving by means of thermic or radiation energy, or chemical agents a peroxide having the formula wherein R represents hydrogen, a hydrocarbon radical, an acyl group or a group of formula and R represents a group of formula II, provided that when R and R represent a group of formula II they are identical, to give a mixture comprising a lactone of formula III and the corresponding unsaturated lactone IVi or IVii, and either separating the lactone lll from said mixture or hydrogenating the aforesaid mixture or the unsaturated compound lVi or IVii, separated from said mixture R", R and n in formula II have the same meaning as in formula III. R R and n in formula II have the same meanings as in formula III.

The cleavage of peroxide 1 can be carried out by using free radical-initiatingtechniques, for example, by supplying thermic or radiation energy, or by using reactants which contain unpaired electrons.

The thermal cleavage can be carried out by heating peroxide I in the presence or absence of organic solvents at a temperature comprised between and 150C. As organic solvents, liquid hydrocarbons with the boiling point in the region of 80C can be conveniently used. Preferably, aromatic hydrocarbons, such as, for example, toluene or xylene, are used. According to a preferred mode of operation a solution of peroxide I in xylene is heated at a temperature comprised between and C. A mixture of 0-, mand pxylene can also be used.

By thermocleavage peroxide I gives a mixture comprising a lactone having the formula III and the corresponding unsaturated lactone Ni, ii. The ratio of the saturated lactone to its unsaturated derivative varies within wide limits and is dependent on the reaction conditions under which the cleavage of peroxide I is carried out. For instance, the influence of the solvent is shown by the fact that when 12-hydroperoxy-l3- oxabicyclo[10.4.0]hexadecane is allowed to cleave in solution in m-xylene a mixture consisting of 83.2 percent of IS-pentadecanolide and 16.8 percent of 15- pentadec-(ll and 12)enolide is obtained. When the same hydroperoxide is allowed to cleave in solution in p-xylene and o-xylene, respectively, mixtures consisting of 70.8 percent and 60 percent of saturated lactone, and 29.2 percent and 40 percent of unsaturated lactone are obtained.

The cleavage of hydroperoxide I can also be promoted photochemically by the action, for example, of ultraviolet light on either the neat hydroperoxide I or a solution of the hydroperoxide I in an organic solvent. As solvents, chlorinated hydrocarbons, such as, for example, chloroform, carbon tetrachloride or trichloroethylene, or ethers, such as dioxan, tetrahydrofuran or monoglyme, can be used.

By photochemical cleavage, as in the case of the thermal process, the epoxide I yields a mixture of saturated and unsaturated lactones.

According to another embodiment of the invention, lactones III are obtained by cleaving peroxide I by means of reducing agents.

Suitable reducing agents comprise inorganic ions that can change their valence state by loss of a single electron, for instance, ions of heavy metals, such as iron, cobalt or copper, or reducing agents commonly known to generate nascent hydrogen, for example, metal combinations such as aluminum, manganese, zinc, iron, cadmium, cobalt, nickel, tin or lead and acids, or an alkali metal and an alcohol, e.g. sodium or potassium in methanol, ethanol or tert.-butanol, or even an alkali metal sulphite, hydrogen sulphite, thiosulphate, dithionate or pyrosulphite in the presence of an organic solvent.

It maybe assumed that with certain of the cleaving agents mentioned above the cleavage of peroxide I follows a mechanism pattern of homolysis wherein the -0 bond of the l I pe1*ox1tie(l3OOR group cleaves in order to give the tures thereof. The temperature at which said reaction can occur is not critical. It is preferable to operate at a temperature comprised between about and about 60C.

A preferred mode of operation comprises adding, at a temperature comprised between 20 and 28C, to a vigorously stirred aqueous buffer solution of sodium sulphite and sodium hydrogen sulphite a solution of peroxide I in chloroform and isopropyl alcohol, decanting the organic phase, extracting the aqueous solution with chloroform and evaporating the combined organic extracts to give a mixture comprising lactones III and Ni, ii.

The mixtures of lactones obtained according to the present invention can be used as such, i.e. without separation of their components, as odoriferous substances. If desired, it is also possible to separate the saturated lactone from its unsaturated derivative by distilling the obtained mixture by means ofa highly effective distillation column. Furthermore, said mixtures can be hydrogenated, for instance, by catalytic hydrogenation at room temperature in the presence of Raney nickel catalyst, in order to give the saturated lactone as sole product. The mixture obtained according to the invention and their individual components are odoriferous substances which develop a more or less characteristic musk-like odour.

The starting materials I, used in the present invention, can be obtained by treating compounds of formula (0x1 CH-R oxide or a hydroperoxide having the formula R -OOH, wherein R represents a hydrocarbon radical, such as an alkyl, e.g. tert.-butyl, a cycloalkyl, an aralkyl or an aryl radical, or an acyl group, e.g. benzoyl. tert.-Butylperoxide is preferred. The peroxides of formula I wherein R and R are the same and represent a group having formula II, can be prepared by treating bicyclic ethers V with hydrogen peroxide in the presence of sulphuric acid at a temperature comprised between about 10 and about 25C, preferably between 12 and 14C, and allowing the reaction mixture to react at that temperature during 20-30 minutes. The peroxide of formula I, wherein the symbol R represents hydrogen, can be obtained by allowing the bicyclic ethers V to react with hydrogen peroxide in the presence of sulphuric acid at a temperature of about 0C during 20-30 minutes.

According to the invention, bicyclic ethers of formula cyclododecanone a compound of formula wherein the symbols R represent hydrogen or one of them a methyl radical and the other hydrogen, reducing the resulting addition compound to the corresponding carbinol, subjecting the obtained carbinol to saponification and decarboxylation in an alkali solution and cyclising the resulting keto-alcohol by means of an acidic agent.

According to a preferred mode of operation, the reduction to the carbinol is carried out by means of sodium borohydride.

As acidic cyclising agents mineral or organic acids, such as hydrochloric acid, phosphoric acid, sulphuric acid, benzenesulfonic acid, p-toluenesulfonic acid or trifluoracetic acid, or acidic diatomaceous earths can be used. I-Ialogens, such as iodine, can also be conveniently used.

The above cyclisation can be carried out by dissolving the product to be cyclised in the presence of the acidic agent into an inert organic solvent such as aliphatic, a cylcoaliphatic, an aromatic, an araliphatic or a chlorinated hydrocarbon, or an ether, such as dioxan. tetrahydrofuran or monoglyme.

Acidic diatomaceous earths in hexane are preferred.

2-Ethoxycarbonyl-cyclododecanone, the starting material in the above process, can be synthesized from cyclododecanone, a cheap commercially available product, according to known synthetic methods [e.g. Tetrahedron I9, 1625 (1963)].

Scheme I hereinbelow illustrates the above described process.

In the above scheme the symbols R have the same 30 p ifi x mpl f omp n mpr y h meaning as indicated for formula VI, various structural formulae shown hereinbefore in- Besides, hicyclic ethers V, used in the process de- Cludei scribed in the present specification for the preparation Z- Y P Y- y t 1O-4-O]heXadeCane,

of lactones II] and Ni, ii, can be synthesized according 35 W P Y' y to known synthetic methods and their preparation as am,

illustrated in Scheme IL di-[l3-oxabicyclo[ l0.4.0]hexadec-l2-yl]peroxide,

In the above Scheme the symbols R and index p have 12-hydroperoxy-l3-oxa-l4-methylbicyclo8 the same meaning as indicated for formula IVii. 10.4.01hexadecane,

The unsaturated lactones IV of the present invention 65 2- ydrop ro y- 3-0xa-l5- y y l form, according to the position of the double bond, two a a isomers, each of them possessing a cisor transl4-m hy -l configuration. These various isomers can be separated 15-methyl-lS-pentadccam by means of preparative vapour phase chromatogra- 14-methyl-IS-pentadecanolide,

phy. l5-hexadecanolide,

l7-heptadecanolide, lo-methylhexadecanolide, l-methy1- l o-hexadecanolide, l7-methyl- 1 7-heptadecanolide, 16-methy1-17-heptadecanolide, cis-l 5-pentadec-1 l-enolide, transl 5-pentadec-1 l-enolide, cis-l S-pentadecl 2-enolide, trans-l 5-pentadec-12-enolide, cis-14-methyl-l S-pentadec-l l-enolide, trans-l4'methyl-l5-pentadec-l l-enolide, cis-l5-methyl-l5-pentadec-l l-enolide, trans-1S-methyl-lS-pentadec-l l-enolide, cisl 4-methy1- 1 5-pentadecl 2-enolide, trans-l4-methyl-l5-pentadec-12-eno1ide, cis- 1 S-methyll S-pentadecl 2-enolide, trans-15-methyl-IS-pentadec-l 2-enolide, cis-l6-hexadec-l l-enolide trans-l 6-hexadec-l l-enolide, cis-l 6-hexadec- 1 Z-enolide, transl 6-hexadecl 2-enolide, cis- 1 5-methyl-16-hexadecl l-enolide, trans-l 5-methy1- 1 6-hexadec-l l-enolide, cis-l5-methyl-16-hexadec-1 2-enolide, trans-l S-methyl- 1 6-hexadec- 1 2-enolide, cis-l6-methyl-16-hexadec-l l-enolide, transl 6-methyll 6-hexadec-l l-enolide, cis-16-methyl-l6-hexadec-l2-enolide, trans-16-methyl-16-hexadec-12-enolide, cis-l 7-heptadec-1 l-enolide, transl 7-heptadec-1 l-enolide, cis-l7-heptadec-12-enolide, trans-1 7-heptadecl 2-enolide, cis' 1 6-methyl-l 7-heptadec-l l-enolide, transl 6-methyll 7-heptadec-l l-enolide, cis-l 6-methyll 7-heptadecl 2-enolide, trans-16-methyl-l7-heptadec-l2-enolide, cis-l 7-methyl-l7-heptadec-l l-enolide, trans-l 7-methyl-17-heptadec-l l-enolide, cis-l 7-methyl-l 7-heptadec- 1 2-eno1ide, transl 7-methyl- 1 7-heptadecl 2-enolide.

The invention will be illustrated in a more detailed manner by the following Examples. In said Examples the temperatures are given in degrees Centigrade.

EXAMPLE 1 A suspension of 12-hydroperoxy- 1 3- oxabicyclo[l0.4.0]hexadecane (439 g) in 2500 ml of xylene was added portionwise under vigorous stirring to 2400 ml of boiling xylene. The reaction mixture was left 10 minutes at reflux temperature then allowed to cool. By evaporation of the volatile components under reduced pressure, there were obtained 519.2 g of crude material, which, by fractional distillation, gave a fraction at b.p. 73-l60/0.3 Torr. This fraction was redistilled by means of a Virgreux column and yielded 313 g of a substance containing 89 of pentadecanolide and 11 percent of l5-pentadec-(ll and 12)-enolide. l2-l-lydroxy-IS-pentadecanolide (98 g) was obtained as by-product.

The mixture of pentadecanolide and 15-pentadec- (l1 and 12)-enolide can be either used directly as it stands as perfuming substance or submitted to catalytic hydrogenation in order to obtain complete conversion to pentadecanolide. In a typical experiment, the cata- Lytlic hydrogenation is carried out as described hereine ow.

To'a solution of 313 g of a mixture of pentadecanolide and l5-pentadec-( 1 1 and 12)-enolide (obtained according to the procedure described hereabove) in 1.5 litre of methanol, 50 g ofa 30 percent Raney nickel suspension and 5 ml of a 10 aqueous solution of Na CO were added and the mixture was shaken in an atmosphere of hydrogen for 3% hours. In the above process, 3600 ml of hydrogen were consumed. The reaction mixture was filtered and the clear filtrate evaporated to dryness. The obtained residue was dissolved in 300 ml of ether and 300 ml of toluene and the resulting solution washed with water until neutral, dried over Na SO, and evaporated in vacuo. 31 1 g of crude prod uct, containing ca. percent pentadecanolide, were thus obtained.

l2-Hydroperoxyl 3-oxabicyclo[ l0.4.0]hexadecane,

used as starting material in the above process, can beobtained as follows:

To a solution of l3-oxabicyclo[10.4.0]hexadec- 1(l2)ene (2222 g, 10 Mole) in 10 litres of 90 percent acetic acid at 0, 52 aqueous solution of hydrogen peroxide (1000 g, 15.3 Mole) and 500 g of concentrated sulphuric acid were added (27 minutes). During the addition of hydrogen peroxide, the temperature of the reaction mixture was kept at l/+l, then at 0 while stirring for 15 additional minutes. 12- Hydroperoxyl 3-oxabicyclo[ lO.4.0]hexadecane (3629 g) was obtained as wet solid product by filtration of the above mixture followed by washing with 3 litres of 50 percent acetic acid and water. After drying 2160 g of product with m.p. 103-114 were obtained.

EXAMPLE 2 A solution of 190 g of di-[13- oxabicyclo[ l0.4.0]hexadec-12-y1]-peroxide in 500 ml of xylene was added dropwise to 600 ml of boiling xylene (70 minutes). After cooling, the reaction mixture was evaporated under reduced pressure and the residue distilled to give 139.4 g of a mixture of 15- pentadecanolide and l5-pentadec-( 1 l and 12)- enolide, b.p. 105l07/O.2 Torr.

This mixture was dissolved in 750 ml of methanol and 25 g of a 30 Raney nickel suspension and 1 ml of a 10 percent aqueous Na CO solution were added to it. Under the same conditions as those described in Example l the mixture was subjected to hydrogenation. One hour was required and 1200 ml of hydrogen were consumed. After the usual treatments [cf. Example 1 139 g of pentadecanolide were obtained.

Di-[--oxabicyclo[ 10.4.0]hexadec-l2-yl]-peroxide, used as a starting material in the above process, can be obtained as follows:

To a solution of l3-oxabicyclo[10.4.0]hexadecl(l2)ene (222.2 g, 1 Mole) in 1 litre of glacial acetic acid at 12, a 52 solution of hydrogen peroxide (400 g) and 200 g of concentrated sulphuric acid were added (20 minutes). After stirring for 30 additional minutes at 8, the mixture was filtered. The peroxide was obtained as a wet solid product by filtration of the above mixture followed bywashing with 450 ml of 50 percent acetic acid and water..After drying, g of di-[l3-oxabicyclo-[10.4.0]hexadec-12-y1]-peroxide having m.p. l34-6 were obtained.

EXAMPLE 3 i I 36 g of a 75 solution of tert.-butylhydroperoxide (0.3 Mole) were added to a solution of 13- 9 oxabicyclo[10.4.0]-hexadec'l(12)ene (44.4 g, 0.2 Mole) in 250 ml of acetic acid. To this mixture 15 g of concentrated sulphuric acid and 100 ml of glacial acetic acid were added at such a rate as to maintain the temperature below 14. After having been kept at 10-12 for 30 additional minutes, the mixture was poured into 1000 ml of ice-cold water and 300 ml of ether and stirred for 10 minutes. The aqueous phase was decanted and extracted with more ether. The combined extracts, after the usual treatments of washing (10 percent aqueous solution of HaHCO and water) and drying (Na SO yielded, by evaporation under reduced pressure, 56 g of crude 12-tert.-butylperoxy-l3- oxabicyclo[ l0.4.0]hexadecane.

A solution of crude hydroperoxide (56 g) in 150 ml of xylene was slowly added under vigorous stirring to 250 ml of boiling xylene (90 minutes). According to the same procedure as that described in Example 1, the mixture of pentadecanolide and -pentadec-( 11 and 12 enolide was obtained in a 40 percent yield (relative to 13-oxabicyclo[10.4.0]hexadec-l(12)-ene).

Pure pentadecanolide was obtained by hydrogenating the above mixture according to Example 1.

l3-Oxabicyclo[l0.4.0]hexadec-l(l2)-ene used for the preparation of the hydroperoxides of Examples 1-3 and 8 can be prepared as follows:

A solution of 8 kg of 1-bromo-3chloropropane in 8 kg of dimethylformamide was added under stirring to a solution of sodium methoxide (2.9 kg, 53.7 Mole) and 2-ethoxycarbonyl-cyclododecanone (12.7 kg, 49.9 Mole) in 55 kg of dimethylformamide. The reaction is exothermic and, by standing 25 minutes, the mixture reached a temperature of 60. It was then left at room temperature during one night. The 2-ethoxy-2-[3- chloropropyl]-cyclododecanone, obtained in the above process, was not isolated from the reaction mixture but was used as it stood for the next step. After addition of anhydrous sodium acetate (5 kg), the reaction mixture was left under stirring at 110-120 during 10 hours, then the dimethylformamide was evaporated off under reduced pressure. The obtained residue, after dilution with litres of toluene, washing with water and evaporation of the volatile components in vacuo, gave the crude 2-ethoxycarbonyl-2-[3-methoxycarbonylpropyl]-cyclododecanone.

This product was mixed with 50 litres of water and 27 kg of a 30 aqueous sodium hydroxide solution. The reaction mixture, after having been kept under stirring at 8590 during 5 hours, was cooled to room temperature and poured into 20 litres of toluene. After separation, the aqueous phase was extracted with more toluene (8 litres) and the combined organic extracts, after the usual treatments of washing and drying, were evaporated under reduced pressure. There were thus obtained 11.3 kg of crude product, which by fractional distillation yielded 9.525 kg of 2-[3-hydroxypropyl1- cyclododecanone, b.p. 138180/0.2 Torr.

A solution of 9.525 kg of 2-(3-hydroxypropyllcyclododecanone and 500 g of 70 percent benzenesulfonic acid in 30 kg of toluene was heated at reflux for 5 hours under stirring. The water (680 ml) formed during the reaction was directly distilled as soon as it formed. The reaction mixture, after cooling to 20, was washed twice with water and neutralised with 20 litres of a 10 percent aqueous solution of NaHCO The organic phase, after separation and washing with water, was evaporated under reduced pressure to yield 9.370 kg of crude product. By fractional distillation, 7.7 kg,

10 of 13-oxabicyclo[10.4.0]hexadec-1( l2)-ene, b.p. 1 10l 14/0.2 Torr, were obtained. The yield, relative to 2-ethoxycarbonyl-cyclododecanone, was 69.3 percent.

EXAMPLE 4 A solution of acrolein (196 g) in 300 ml of methanol was added dropwise at 0-3 to a vigorously stirred solution of 2-ethoxycarbonyl-cyclododecanone (763 g, 3 Mole) and sodium methoxide (15 g) in 2 litres of methanol (1 1/2 hours). The reaction mixture was then left at 0 during 30 additional minutes. The 2- ethoxycarbonyl-2-[3-oxypropyl]-cyclododecanone, obtained in the above process, was not isolated from the reaction mixture but was used as it stood for the next step.

To the above mixture sodium borohydride (30 g, 0.79 Mole) was added portionwise under stirring at 0- 3, and the solution was kept at this temperature until thinlayer chromatographic analysis (SiO benzeneethyl acetate 9:1) revealed complete disappearance of the starting material.

A 30 percent aqueous solution of sodium hydroxide (330 ml, 3.3 Mole) was added during 20 minutes to the above reaction mixture kept under vigorous stirring. The temperature, which at the beginning of the reaction was at 0, increased up to 20 and it was then brought at -70 by means of an external water bath. The mixture was kept at this temperature during 3 hours and the sodium hydrogen carbonate (230 g) which precipitated during the above operation was isolated by filtration. The clear filtrate, after evaporation of the volatile components, gave a residue which, after dilution with 4 litres of water, was extracted with 2 litres of toluene. The organic phase, after the usual treatments of washing (4 litres of water), neutralisation (200 ml of 25 percent sulphuric acid) and drying, yielded by evaporation 740 g of crude product. The subsequent fractional distillation of the crude product gave 609 g of 2-[3-hydroxypropyl]-cyclododecanone, b.p. -l60 /0.1 Torr. The product thus obtained was used as it stood for the next step. IR: 3420, 1700 cm".

2-[3-hydroxypropyl]-cyclododecanone (309 g) in 1000 ml of n-hexane was treated with 60 g of acidic diatomaceous earth. The reaction vessel was fitted with a lateral distillation apparatus in order to enable the direct distillation of the water formed during the reaction. 46 ml of water were recovered. After cooling, the suspension was filtered and the solid washed with hexane.

By evaporation of the volatile components, there was obtained a residue (600 g) which, by fractional distillation, yielded 510 g of l3-oxabicyclo[10.4.0]-hexadec- 1(12)-ene, b.p. 116-120/0.1 Torr. IR: 1660 cm By replacing in the above process acrolein by methacrolein and by methyl vinyl ketene respectively, 15- methyl-13-oxabicyclo[10.4.0]hexadec-1(12)-ene and 14-methyl-13-oxabicyclo[10.4.0]hexadec-1(12)-ene were obtained. The analytical constants of these compounds were as follows: 15-methyl-13- oxabicyclo[l0.4.0]hexadec-1(12)-ene: d 0.9623; n 1.5018. l4-methyl-13-oxabicyclo[l0.4.0]hexadec-1( l2)-ene: d 0.9581; u 1.5037.

EXAMPLE 5 1 According to the same procedure as that described in Example 1, l2-hydroperoxy-13-oxa-14- methylbicyclo[10.3.0]-pentadecane (17.3 g) in xylene (100 ml) was decomposed in boiling xylene (100 ml). The residue (18.2 g) obtained by the usual treatment (cf. Example 1) gave by fractional distillation 13.7 g of a mixture of 14-methyl-14-tetradecanolide and 14-methyl-14-tetradec-(1 1 and 12)-enolide. By hydrogenating the above mixture 9 g of pure 14-methyl-14- tetradeconalide, b.p. 105/0.1 Torr, were obtained. This product is a new compound which possesses very interesting odoriferous properties.

l4-Methyl-12-hydroperoXy-13-oxabicyclo[10.3.0]-

pentadecane, used as starting material for the above process was prepared as follows:

To a solution of 14-methyl-l3-oxabicyclo[10.3.0]- pentadec-l(l2)-ene. (22.2 g, 0.1 Mole) in 100 ml of 90 percent acetic acid at a 52 percent aqueous solution of hydrogen peroxide and g of concentrated sulphuric acid were added under stirring (3 minutes). According to the same procedure as that described in Example 1, 17.3 g of product were obtained. After recrystallisation from ethylacetate the pure 12-hydroperoxy-l 3-oxa-14- methylbicyclo[10.3.0]pentadecane had m.p. l18120.

14-Methyl-13-oxabicyclo[10.3.0]pentadec- 1(12)-ene, used as starting material for the preparation of the above peroxide, was obtained as follows: 2- Ethoxycarbonyl-cyclododecanone (254.3 g, l Mole) in 1000 m1 of dimethyl 1 formamide was added to a solution of sodium methoxide (59.4 g, 1.1 Mole) in 800 ml of dimethylformamide. To this mixture allylbromide 132 g, 1.1 Mole) in 200 ml of dimethylformamide was added at 50 under vigorous stirring (2 hours). After standing overnight at 50 under stirring, the mixture was subjected to evaporation under reduced pressure. The residue thus obtained was treated with 750 ml of water and 30 m1 of glacial acetic acid and extracted with toluene. By evaporation of the combined organic extracts and fractional distillation of the residue under high vacuum (0.03 Torr), 266.9 g of 2-allyl-2- ethoxycarbonyl-cyc1ododecanone were obtained, m.p. 58-60.

A mixture of 200 g of 2-allyl-2-ethoxycarbonylcyclododecanone, 400 ml of ethanol and 300 ml of a 30 percent aqueous sodium hydroxide solution was stirred during 4 hours at reflux temperature. After evaporation of the alcohol at reduced pressure, the mixture was treated with toluene and this solution washed with an aqueous solution of NaCl until neutral. The aqueous phase was extracted with more toluene and the combined organic extracts were evaporated to dryness. The residue thus obtained (136.5 g) gave by fractional distillation 1 16.1 g of 2-allylcyclododecanone, b.p. 928/0.03 Torr.

63 g. of 2-allyl-cyclododecanone were added at 0 over a period of 20 minutes to 600 g of 90 H SO under vigorous stirring. After 2 additional hours of stirring, the temperature of the reaction mixture was increased to and the mixture was then poured onto water/ice. The extraction with ethyl acetate followed by the usual treatments of washing, drying and evaporation of the combined organic extracts gave a crude product (65 g) which, by fractional distillation, yielded 54 g of l4-methyl-13-oxabicyclo[ l0.3.0]pentadec- 1(12)-ene, b.p. 105/0.1 Torr.

EXAMPLE 6 A suspension of 12-hydroperoxy- 1 3- oxabicyclo[l0.4.0]hexadecane (25.6 g) in 500 ml of EXAMPLE 7 10 g of di-[ l3-oxabicyclo[ l0.4.0]hexadec-l2- yl]peroxyde were irradiated according to the same procedure as that described in Example 6. 11 g of crude material yielded by fractional distillation 6 g of a mixture ca. 1:1 of 15-pentadecanolide and IS-pentadec- (11 and 12)-enolide, b.p. 956/O.1-0.2 Torr.

EXAMPLE 8 A solution of 665 g of. 12-hydroperoxy- 13- oxabicyclo[l0.4.0]hexadecane in 5 litres of chloroform and 1.5 litres of isopropylalcohol was added dropwise (2.1/4 hours) to a vigorously stirred neutral aqueous solution (pH ca. 7.0) of sodium sulphite (375 g) and sodium hydrogen sulphite g). The temperature, which at the beginning of the reaction was at 21,

increased rapidly to 2728 and the addition of the peroxide was set at such a rate as to maintain the temperature of the reaction mixture within said range.

After subsequent stirring during hour, a thin-layerchromatographic analysis (SiO benzene/ ethyl acetate 9:1) revealed total disappearance of the starting material. The organic phase was decanted and the aqueous solution extracted with 300 ml of chloroform. The combined extracts were washed twice with 4 litres of a 10 aqueous solution of sodium hydrogen carbonate and water, dried over anhydrous sodium sulphate and evaporated to dryness under reduced pressure.

The residue (860 g) thus obtained yielded 567 g of a mixture consisting of 15-cyclopentadecanolide (ca. 50 15-pentadec-(11 and l2)-enolide (ca. 25 12-hydroxy-lS-pentadecanolide (7.6 and l3-oxabicyclo[ l0.4.0]hexadecl(12)-ene (17.4 as revealed by vapour phase chromatographic analysis.

The mixture (567 g) obtained in the above process was subjected to hydrogenation according to the same procedure as that described in Example 1. The following quantities were used:

1.5 litres of ethanol g of a 30 percent Raney nickel suspension 30 ml of a 5 percent aqueous solution of Na CO 12.5 litres of hydrogen were consumed in a complete hydrogenation period of 17 hours. The residue obtained by evaporation of the volatile components under reduced pressure was diluted with ca. 700 m1 of ether and the mixture washed with water until neutral. The

organic phase, subjected to the usual treatments of drying and evaporation, gave by distillation 545 g of a mixture, b.p. 155/0.1 Torr, consisting of 15- cyclopentadecanolide (76.2 12-hydroxy-15- pentadecanolide (8.4 and 13oxabicyc1o[10.4.0- ]hexadec-1(l2)-ene (15.4

Fractional redistillation of the above mixture gave 380 g of l5-cyclopentadecanolide, b.p. 101-105/0.1 Torr.

By replacing in the above process 12-hydroperoxy- 13-oxabicyclo[ l0.4.0]hexadecane by 12-hydroperoxy- 13 13-oxa-14-methylbicyclo[10.4.0]hexadecane and 12- hydroperoxy-l3-oxa-15-methylbicyclo[ lO.4.0]hexadecane respectively, mixtures consisting of IS-methyl- IS-pentadecanolide, -methyl-15-pentadec-(11 and 12)-enolide and 12-hydroxy-15 -methyl-l5- pentadecanolide, and l4-methyl-1S-pentadecanolide, 14-methyl-l5pentadec-( 11 and 12)-enolide and 12- hydroxy-14-methyl-IS-pentadecanolide were obtained with similar yields.

By hydrogenation of said mixtures and subsequent fractional distillation lS-methyl-IS-pentadecanolide (df 0.9399, n 1.4700) and 14methyl-15- pentadecanolide (d 0.9499, n 1.4728) were obtained.

l2-Hydroperoxy-l 3-oxa-14-methylbicyclo[ 10.4.0- ]hexadecane and l2-hydroperoxy-13oxa-l5- methy1bicyclo[10.4.0]hexadecane can be prepared according to the same procedure as that described in Example 1 for the preparation of l2-hydroperoxy-l3- oxabicyc1o[l0.4.0]hexadecane. They showed the following analytical data.

12-hydroperoxy-l3-oxa-14-methylbicyclo[10.4.0- ]hexadecane: m.p. 109-110, dec. p. ca. 140.

12-hydroperoxy-l3-oxa-15-methy1bicyclo[10.4.0- ]hexadecane: m.p. 106108, dec. p. ca. 140.

1 claim:

1. Method for preparation of lactones containing 14 to 17 ring carbon atoms having the formula l (cn cram III wherein R and R represent hydrogen or one of them a methyl radical and the other hydrogen and n repre" sents an integer from zero to 3, which comprises cleaving the oxygen to oxygen band by means of a reducing agent of a peroxide having the formula wherein R represents hydrogen, a lower hydrocarbon radical selected from alkyl,cycloa1kyl, aryl and aralkyl, a lower alkanoyl group or a group of formula (Cllg IV i containing one double bond in one of the positions indi cated by the dotted lines, and wherein r is zero or 1, or, when n is 1 to 3, the formula (Cll 0 CH n wherein m is l or 2 and p is an integer from zero to 2, and either separating the lactone 111 from said mixture or hydrogenating the aforesaid mixture or the unsaturated compound lVi, ii, separated from said mixture.

2. Method according to claim 1 wherein there is used as peroxide a compound of the formula I wherein R and R represent a group having the formula II.

3. Method according to claim 1 wherein there is used as a peroxide di-[13-oxabicyclo[10.4.0]hexadec-l2- yl]-peroxide, 12-hydroperoxy-l3-oxabicyclo[10.4.0- ]hexadecane or 12-tert.buty1peroxy-13- oxabicyclo[10.4.0]hexadecane and there is obtained a mixture consisting of IS-pentadecanolide and 15- pentadec-( 11 and 12)-eno1ide.

4. Method according to claim 1 wherein there is used as peroxide 12-hydroperoxy-13-oxa-14- methylbicyclo[ l0.4.0]hexadecane and there is obtained 15-methyl-15-pentadecanolide and 15-methyl-l5-pentadec-(1l and l2)-enolide.

5. Method according to claim 1 wherein there is used as peroxide 12-hydroperoxy-13-oxa-15- methylbicyclo[10.4.0]hexadecane and there is obtained 14-methyl-1S-pentadecanolide and 14-methyl-15-pentadec-(ll and 12)-enolide.

6. Method according to claim 1 wherein there is used as peroxide 12-hydroperoxy-l4methy1-l3- oxabicyclo[l0.3.0]pentadecane and there is obtained a mixture comprising l4-methyl-14-tetradecanolide and 14-methyl-14-tetradec-(11 and 12)-eno1ide.

7. Method according to claim 1 wherein there is used as a reducing agent an alkali metal sulphite, hydrogen sulphite, thiosulphate, dithionate or pyrosulphite.

8. Method according to claim 7 wherein a mixture of sodium sulphite and sodium hydrogen sulphite is used in the presence of chloroform.

9. Method according to claim 8 wherein the cleavage of the peroxide is carried out by adding, at a temperature comprised between 20 and 28C, to a vigorously stirred aqueous buffer solution of sodium sulphite and sodium hydrogen sulphite a solution of the peroxide in chloroform and isopropylalcohol, decanting the organic phase, extracting the aqueous solution with chloroform and evaporating the conbined organic extracts to give a mixture comprising lactones III and IVi, ii.)

10. Method according to claim 2 wherein the obtained mixture of lactones is subjected to catalytic hydrogenation at room temperature and atmospheric pressure, and there is obtained IS-pentadecanolide.

11. Method according to claim 1 wherein the obtained mixture of lactones is subjected to catalytic hydrogenation at room temperature and atmospheric pressure, and there is obtained pentadecanolide.

12. Method according to claim 1 wherein the obtained mixture of lactones is subjected to catalytic hydrogenation at room temperature and atmospheric 1 5-methyl-15 pressure, and there is obtained l4-methyl-l5- drogenation at room temperature and atmospheric pentadecanolide. pressure, and there is obtained l4-methyl-14- 13. Method according to claim 1 wherein the obtetradecanolide.

tained mixture of lactones is subjected to catalytic hy- UNITED STATES PATENT AND TRADEMARK OFFICE CERTIFICATE OF CORRECTIGN PATENT NO. 3,890,353

DATED June 17, 1975 INVENTOR(S) Joseph J. Becker It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

[SEAL] Column 1, line 53, "performing" should be -perfuming- Column 2, line 14, "mixture R R and n." should be mixc'ure. R R and n.

"of alcohol" Column 3, line 23, should be of an alcohol--.

Column 4 lines 57-58, "such as aliphatic," should be -such as an allphatic,.

Column 5, line 36, "as" should be -is-.

Column 6, line 62, "l2-hydroperoxy-l3-oxak-l4-methylbioyclo8" should be l2-hydropero yl3-oxa-l4-methylbicyclo[--,

Column 8, line 51, "Di- [-oxabicyclo [10.4.0]hexadec-l2- yl]-peroxide," should be -Di-[l3oxabicyclo[l0.4.0] hexadec-lZ-yl]peroxide,.

Column 10, line 42, "b.p. ll5l60 l65/0.l Torr."

should be -b.p. ll5l60-l65/0.l Torr.-.

Column 10, line 58, "ketene" should be ketone-.

Column 13, line 40,

"band" should be -bond-.

Signed and Scaled this Attest:

RUTH C. MASON Arresting Officer C. MARSHALL DANN Commissioner ofPatents and Trademarks 

1. METHOD FOR PREPARING OF LACTONES CONTAINING 14 TO 17 RING CARBON ATOMS HAVING THE FORMULA
 2. Method according to claim 1 wherein there is used as peroxide a compound of the formula I wherein R1 and R2 represent a group having the formula II.
 3. Method according to claim 1 wherein there is used as a peroxide di-(13-oxabicyclo(10.4.0)hexadec-12-yl)-peroxide, 12-hydroperoxy-13-oxabicyclo(10.4.0)hexadecane or 12-tert.butylperoxy-13-oxabicyclo(10.4.0)hexadecane and there is obtained a mixture consisting of 15-pentadecanolide and 15-pentadec-(11 and 12)-enolide.
 4. Method according to claim 1 wherein there is used as peroxide 12-hydroperoxy-13-oxa-14-methylbicyclo(10.4.0)hexadecane and there is obtained 15-methyl-15-pentadecanolide and 15-methyl-15-pentadec-(11 and 12)-enolide.
 5. Method according to claim 1 wherein there is used as peroxide 12-hydroperoxy-13-oxa-15-methylbicyclo(10.4.0)hexadecane and there is obtained 14-methyl-15-pentadecanolide and 14-methyl-15-pentadec-(11 and 12)-enolide.
 6. Method according to claim 1 wherein there is used as peroxide 12-hydroperoxy-14-methyl-13-oxabicyclo(10.3.0)pentadecane and there is obtained a mixture comprising 14-methyl-14-tetradecanolide and 14-methyl-14-tetradec-(11 and 12)-enolide.
 7. Method according to claim 1 wherein there is used as a reducing agent an alkali metal sulphite, hydrogen sulphite, thiosulphate, dithionate or pyrosulphite.
 8. Method according to claim 7 wherein a mixture of sodium sulphite and sodium hydrogen sulphite is used in the presence of chloroform.
 9. Method according to claim 8 wherein the cleavage of the peroxide is carried out by adding, at a temperature coMprised between 20 and 28*C, to a vigorously stirred aqueous buffer solution of sodium sulphite and sodium hydrogen sulphite a solution of the peroxide in chloroform and isopropylalcohol, decanting the organic phase, extracting the aqueous solution with chloroform and evaporating the conbined organic extracts to give a mixture comprising lactones III and IVi, ii.)
 10. Method according to claim 2 wherein the obtained mixture of lactones is subjected to catalytic hydrogenation at room temperature and atmospheric pressure, and there is obtained 15-pentadecanolide.
 11. Method according to claim 1 wherein the obtained mixture of lactones is subjected to catalytic hydrogenation at room temperature and atmospheric pressure, and there is obtained 15-methyl-15-pentadecanolide.
 12. Method according to claim 1 wherein the obtained mixture of lactones is subjected to catalytic hydrogenation at room temperature and atmospheric pressure, and there is obtained 14-methyl-15-pentadecanolide.
 13. Method according to claim 1 wherein the obtained mixture of lactones is subjected to catalytic hydrogenation at room temperature and atmospheric pressure, and there is obtained 14-methyl-14-tetradecanolide. 